The present invention relates generally to an improved device for detecting and measuring the concentration of gaseous hydrogen dissolved in a fluid.
More especially, this invention relates to an improved detecting and measuring device in which the concentration of gaseous hydrogen dissolved in a fluid is determined by the measure of an electric current generated by electro-chemical oxidation of the gaseous hydrogen at an electrode of detection.
A device of the above-mentioned type is already known and forms the subject matter of Canadian Pat. No. 1,054,223 issued on May 8, 1979 in the name of HYDRO QUEBEC. The detecting and measuring device disclosed in this patent comprises; a polymeric membrane permeable to hydrogen gas in contact with the fluid; an electrolyte capable of producing oxidation of the hydrogen gas diffused through the polymeric membrane at a first electrode and reduction of an oxygen-containing gas, such as air, at a second electrode; a measuring device connected across the electrodes for measuring the intensity of the electrical current generated by the electrochemical reaction of oxidation of the hydrogen gas, this intensity being proportional to the concentration of hydrogen in the fluid.
This already known device is essentially to provide an accurate diagnosis of the incorrect operation of transformer, a circuit breaker, a reactance or any electrical apparatus using a dielectric liquid as insulating substance. It is indeed well known that, in the event of a disturbance or malfunction of one of the abovementioned apparatus due to a too high working temperature or a high electrical discharge, there is production of hydrogen gas in the insulating liquid. Accordingly, it can be easily understood that the utilization of a device allowing for immediate detection of an increase of the concentration of gaseous hydrogen dissolved in the insulating liquid, is advantageous since it allows immediate diagnosis of the incorrect operation of the electrical apparatus on which the device is mounted, and, when this incorrect operation is timely located, to avoid irrepairable ruin of the apparatus.
The various experiments that were carried out by the applicant on the device disclosed in the above-mentioned Canadian Patent, have shown however that while the basic concept is valid, the various practical embodiments disclosed in the above Canadian patent have drawbacks when they are used for a relatively long period of time in certain regions. These would be those regions where the climatic conditions are extremely hard, or where they would be very difficult to reach and thus require utilization of very reliable devices. These experiments showed that the various embodiments disclosed in the above-mentioned Canadian patent were often subject to leak, particularly of electrolyte, making the device inoperative. These experiments also showed that these various embodiments as a unit were cumbersome, since it is necessary to remove practically all the internal elements of the device one by one in order to reach one of these elements or to introduce or change the electrolyte. These experiments further showed that in the regions subject to high variations of temperature, such as, for example, The Canadian Far North, the measurements obtained were very unsteady and very difficult to follow and read.